On Wed, Jun 22, 2016 at 3:05 AM, Stefan Magnus Landrø <stefan.lan...@gmail.com> wrote: > Hi Benson, > > Have you considered implementing a custom > https://hc.apache.org/httpcomponents-client-ga/httpclient/apidocs/org/apache/http/conn/DnsResolver.html > that handles DNS changes in a better way than the default implementation? > You could probably use http://www.xbill.org/dnsjava/ and lookup names > directly with the amazon NS?
Thanks for reminding me to ask about that. Does HC call the resolver as part of deciding whether to keep a connection or not? The problem as we see it is this: the DNS mapping for an ELB changes, and a minute later the connections to it become useless but don't necessarily get properly closed with a FIN by the ELB. I've written some goofy code that notices when the address resolution changes for any of the ELB's we care about, and when it does it calls 'closeIdleConnections' with a time of 0. On the other hand, I don't think we're currently having any problems getting InetAddress.getByName to keep up with Amazon, but your suggestion would be safer. > > Stefan > > 2016-06-20 19:57 GMT+02:00 Benson Margulies <bimargul...@gmail.com>: > >> We use the async http components library to connect various components >> in a system that is deployed, in some cases, on AWS. When it's >> deployed on AWS, there are ELBs involved. >> >> Like some other people, we've having various trauma dealing with the >> very dynamic environment of AWS ELBs, which includes constant DNS >> changes and some other issues. So far, we've been making our HC >> configuration more and more complex. I'm wondering if we should back >> off and make it simpler -- make a new connection for each request. >> Obviously, this will be somewhat slower and more expensive, but at the >> moment we might prefer a slower and more expensive approach that works >> to one that occasionally gets lost. >> >> I appreciate that even making new connections all the time won't >> compensate for all possible DNS problems -- if Java itself caches a >> stale name->address translation, making a new connection will fail >> just as effectively as anything else. >> >> Does anyone out there have advice to share (other than running away from >> ELB)? >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: httpclient-users-unsubscr...@hc.apache.org >> For additional commands, e-mail: httpclient-users-h...@hc.apache.org >> >> > > > -- > BEKK Open > http://open.bekk.no > > TesTcl - a unit test framework for iRules > http://testcl.com --------------------------------------------------------------------- To unsubscribe, e-mail: httpclient-users-unsubscr...@hc.apache.org For additional commands, e-mail: httpclient-users-h...@hc.apache.org
